1. Field of the Invention
The present invention relates to a display device on which a self-luminous element, particularly an organic EL element is arranged in a matrix form and a method for driving the same.
2. Description of the Related Art
A plurality of pixels including self-luminous elements such as organic EL elements is arranged in a matrix form on the display area of the display apparatus using the self-luminous elements (hereinafter referred to as a self-luminous display device). The luminance of each pixel is determined by an amount of current or voltage supplied to the self-luminous element via a driving circuit. For this reason, it is necessary to accurately control an amount of current or voltage flowing into the self-luminous element included in each pixel to perform an accurate gradation display on the spontaneous light emitting display device.
A driving circuit for controlling an amount of current or voltage supplied to the self-luminous element includes a pixel circuit provided for each pixel and a peripheral circuit for controlling the pixel circuit provided around a display area. A switching element (an active element, hereinafter, referred to as a transistor) such as a thin-film transistor is used in these circuits.
The transistor has a variation in characteristics such as a threshold (Vth) and mobility (μ) resulting from a variation in a production process. The variation appears as a display unevenness when an image is displayed. Japanese Patent Application Laid-Open No. 2006-084899 discusses a display device provided with a threshold cancel circuit for each pixel circuit to avoid the influence of variation in threshold Vth and mobility, as a technique for suppressing a variation in characteristic of the transistor.
In the conventional display device discussed in Japanese Patent Application Laid-Open No. 2006-084899, digital video data input into the display device from the outside are converted into gradation data which is an analog data voltage and transmitted to each pixel by a gradation data output circuit arranged outside the display area. If a transmission distance is long, the gradation data which is an analog data voltage are influenced by a noise and changed. Therefore, even if variation in the characteristics of the transistor is corrected, a transmission noise is added to the gradation data to preclude the display unevenness from being sufficiently corrected.